Present study was carried out to make it clean whether an electrocardiogram-breath video recording system has effective monitoring on the condition of children's emotions under dental treatment. The condition of emotions were monitored by heart rate, respiratory rate, behavioral patterns and changes of voice.Emotional changes were recorded everywhere from a subject and these were not affected from his action in recording by the system. Pulse and breath were taken out from 3 electrodes attached to the right infraclavicular point and the both sides infra-axillary on the horizontal line of the xiphisternum. A radio was held in waist bag so that the radio telemetrically offer the informations of pulse and breath to a receiver. The information were recored on the right audio zone video tape, the changes of voice were registered on the left and the behavioral patterns were video-taped on the picture zone.Whenever analysis is necessary these emotional informations wrote on a chart thermal array recorder was utilized. The heart rate was the positive correlation with the emotional change under dental treatment. It was clear that the system was easy to observe the behavioral patterns and the change of voice. As regard to the respiratory rate attributed from light breath to breathing stop is difficult of relate. Further detailed study are required on the respiratory rate.